JPH0221531Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a drive device for an oil pump of a chain saw for supplying lubricating oil to the sliding parts of the saw chain.

(b) Prior art and problems to be solved Conventionally, in the oil pump drive device of this type of chain saw, the drive gear 25 is press-fitted into the crankshaft 5, shrink-fitted, etc., as shown in FIG. In some cases, the sprocket 13 was fixed and the sprocket 13 was rotatable via the bearing 15. This system has the disadvantage that the oil pump is driven and oil is supplied even when the engine is at idle, the centrifugal clutch 7 is disconnected, the sprocket 13 is stopped, and the saw chain is not rotating. For this reason, as shown in Figure 5,
The boss portion 9 of the centrifugal clutch 7 is fixed to the crankshaft 5, the sprocket 13 is rotatably supported by the crankshaft 5 via a bearing 15 and is integrally fixed to the clutch drum 17, and the crankshaft 5
A driving gear 25 that is rotatably supported by the sprocket 1 and drives the oil pump is sequentially arranged in parallel with the crankshaft 5, and the sprocket 13 and the driving gear 25 are directly engaged to transmit rotation.
Thrust washer 2 is installed between 3 and drive gear 25.
However, the internal gear-shaped locking portion 35 for directly locking the sprocket 13 and the drive gear 25 had a complicated structure, making machining difficult.

(c) Means and action for solving the problem In the present invention, the boss is fixed to the crankshaft, the sprocket and the drive gear are rotatably mounted on the crankshaft, and the sprocket and the drive gear are provided between the sprocket and the drive gear. A plate-shaped thrust washer is bent to form a locking part that locks on the sprocket on one side, and a locking part that locks on the drive gear is formed on the other side by bending, so that the sprocket and the drive gear can be connected to the thrust washer. When the saw chain is stopped during idle rotation, the oil supply pump does not operate, which prevents unnecessary consumption of lubricating oil, and is easy to manufacture by press molding. By using a thrust washer to lock between the easily machined locking groove on the inner diameter of the drive gear and the teeth of the sprocket, there is no need for a locking part that is difficult to process like a conventional internal gear. It has a simple structure and is easy to process.

(d) Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1 to 4, a crankshaft 5 is rotatably supported in a crankcase 3 of an engine provided in a main body case 1 of a chain saw, and a boss portion 9 of a centrifugal clutch 7 is attached to an outer tip of the crankshaft 5. is threaded part 1
They are screwed together by 1. A sprocket 13 is disposed in parallel inside the boss portion 9 and engages with a saw chain (not shown), and is rotatably supported on the crankshaft 5 via a bearing 15. The center portion of the clutch drum 17 provided close to the outer periphery is integrally fixed. A screw-shaped drive gear 25 is arranged parallel to the inside of the sprocket 13 and engages with a gear 23 provided on a drive shaft 21 of the oil pump 19, and is rotatably supported by the crankshaft 5. A thrust washer 27 is interposed between the sprocket 13 and the drive gear 25 and fits onto the crankshaft 5 to hold the side surface of a saw chain (not shown) that engages with the sprocket 13. A locking portion 29 that is bent to protrude is locked to the valley of the sprocket 13, and a locking portion 31 that is bent to the other side and projected is locked to a locking groove 33 provided in the inner diameter portion of the drive gear 25. , sprocket 1
3 and the drive gear 25 are provided so as to rotate together.

In the above configuration, the centrifugal clutch 7 rotates together with the crankshaft 5 when driven by the engine. When this rotation exceeds a predetermined rotational speed, the centrifugal clutch 7 comes into contact with the inner surface of the clutch drum 17 due to centrifugal force, and the sprocket 13 rotates together with the clutch drum 17. ) rotates to perform wood cutting operations. The thrust washer 27 supports the side of the saw chain, and the locking portion 2
Since the sprocket 13 and the drive gear 25 are engaged with each other via the thrust washer 27 by the sprocket 13 and the drive gear 25, the drive gear 25 rotates and the oil pump 19 is driven via the gear 23. Lubricating oil is supplied. When the engine is idling, the centrifugal clutch 7 does not come into contact with the clutch drum 17, and the sprocket 13 and drive gear 25 do not rotate. That is, when the saw chain does not rotate, oil is not supplied.

(e) Effect of the invention Since the invention has the configuration as described in the claims, when the saw chain is stopped,
Since no oil is supplied, wasteful consumption of lubricating oil can be prevented, and the structure is simple, easy to process, and inexpensive to manufacture.

Note that FIGS. 5 and 6 show a first conventional example, in which the sprocket 13 and the internal gear-shaped locking portion 35 provided on the drive gear 25 are directly locked to transmit rotation. There is. FIG. 7 shows a second conventional example, in which a drive gear 25 is press-fitted and fixed to the crankshaft 5, and the oil pump 19 is driven to supply oil even when the engine is idling. .

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented in other embodiments as well. Further, the symbols shown in the claims do not limit the technical scope of the present invention.

[Brief explanation of drawings]

Figure 1 is a side sectional view of one embodiment of the present invention;
Figure 3 shows the - line and - line in Figure 1, respectively.
4 is a perspective explanatory view of the last washer, FIG. 5 is a side sectional view of the first conventional example, and FIG. 6 is a front sectional view of the line.
The figure is a front cross-sectional view taken along the - line in Figure 5, and Figure 7 is a cross-sectional view taken along the - line in Figure 5.
FIG. 2 is a side sectional view of a conventional example. 5...Crankshaft, 7...Centrifugal clutch, 9...
... Boss part, 13 ... Sprocket, 17 ... Clutch drum, 19 ... Oil pump, 25 ... Drive gear, 27 ... Thrust washer, 29,3
1...Locking part.

Claims (1)

[Scope of utility model registration request] A boss portion 9 of the centrifugal clutch 7 is fixed to the crankshaft 5, a sprocket 13 is rotatably supported by the crankshaft 5 and is integrally fixed to the clutch drum 17, and a sprocket 13 is rotatably supported by the crankshaft 5. A drive gear 25 for driving the oil pump 19 is sequentially arranged in parallel, and the sprocket 1 is attached to one side of a plate-shaped thrust washer 27 interposed between the sprocket 13 and the drive gear 25.
The sprocket 13 and the drive gear 25 are connected to the thrust washer 27. A driving device for an oil pump for a chain saw, characterized in that it is provided to integrally rotate through a chain saw.